1. Field of The Invention
This invention relates generally to ultra-narrow road vehicles.
2. Prior Art
A conventional automobile or four-wheeled vehicle has one or more rows of seats for at least two people in each row, and is typically about 6 feet (1.83 meters) wide. A conventional two-wheeled motorcycle seats one to two people in front-and-back or tandem seating, and is typically about 3 feet (0.92 meter) wide. Vehicles with two to three wheels are classified as motorcycles, and vehicles with four wheels are classified as automobiles. In the United States, each lane of roadway is about 12 feet (3.66 meters) wide for accommodating one automobile, or up to two motorcycles side-by-side with enough clearance between the motorcycles. Motorcycles are narrow enough to drive between automobiles in adjacent lanes when traffic is congested, and can park between them perpendicularly to the curb. Automobiles are most often used for carrying only a single person, particularly for commuting. Considering the far greater space, material, and fuel consumed by automobiles compared to motorcycles, automobiles are much less efficient at transporting people.
Despite the advantages of motorcycles in heavy traffic, parking, and efficiency, automobiles are preferred by the vast majority of people because they are much easier and safer to drive, and their enclosed cabins provide comfort and sufficient carrying capacity. Therefore, the freeways and streets of urban areas everywhere are congested with automobiles. As the economy and population of urban areas grow, traffic and parking problems are deepened. City governments try to alleviate these problems by urging the public to use carpooling and public transportation. However, these measures have only been met with limited success, because people are reluctant to give up the freedom and convenience they enjoy with their private vehicles. The only remaining solution is to expand roadways, but such a solution is extremely expensive, and often impossible due to the lack of available space.
Narrow body enclosed vehicles have been proposed for increasing transportation efficiency by carrying one or more people in tandem seating. Such vehicles have three or more wheels to keep them upright when stopped. Whereas a conventional automobile is wide enough to be inherently stable in a turn, a truly narrow vehicle is too narrow to avoid falling over onto its side in a turn unless it is stabilized by a stabilizing device. U.S. Pat. No. 4,484,648 to Jephcott and U.S. Pat. No. 4,283,074 to Tidwell disclose vehicles each arranged to tilt or roll toward the inside of a turn by moving the suspension or passenger cabin. In practice, the amount of tilt required is dependent upon the speed and radius of a turn, and the vehicle body must be under precise electronic and hydraulic control. Such tilting systems are complicated and expensive. Further, when an electrical or mechanical failure occurs in the tilting system, the vehicle will go out of control.
U.S. Pat. No. 4,313,517 to Pivar discloses a three-wheeled, wide body vehicle with side-by-side or abreast seating for two people. It has a low center of gravity which is provided by a lightweight cabin positioned on top of batteries. However, the small batteries which are disclosed almost certanly do not provide enough stability. The abreast seating makes it about as wide as a conventional automobile, so that two of such vehicles cannot fit side-by-side on the same lane. The lightweight cabin provides very little crash and weather protection. Further, it has a top speed of only 20 m.p.h. (33 k.p.h.), so that it can never be a commercially viable replacement for conventional automobiles. Even if its power train is modified to enable a higher top speed, its three wheels cannot provide enough turning stability at higher speeds.
All of the prior art vehicles suffer from excessive width, insufficient turning stability, or a lack of safety and comfort, so that none of them are commercially viable. It is clearly difficult to provide a commercially viable combination of features. There is no teaching in any prior art for the importance of a high rollover threshold, which is the maximum allowable lean or tilt from which the vehicle will still right itself onto its wheels. Without a suitably high rollover threshold, a narrow vehicle will fall over onto its side in a turn.